Device for removal of ash and slag from a furnace for the burning of waste or the like



United States Patent lnventor Wolfgang A. Schumann Weidenstieg 22b, Hannoversch-Munden, Germany" Appl. No. 740,657 Filed June 27, 1968 Patented Sept. 22, 1970 Priority June 27, 1967 Germany No. 1,551,852

DEVICE FOR REMOVAL OF ASH AND SLAG FROM A FURNACE FOR THE BURNING 0F WASTE OR THE LIKE 9 Claims, 5 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 473,692 4/1892 Carrington 110/170 946,553 1/1910 Mitchell 110/170 2,862,463 12/1958 Duncan 110/170 Primary Examiner-Kenneth W. Sprague Attorney-Stevens, Davis, Miller and Mosher ABSTRACT: An apparatus for the removal of ash and slag from a furnace having a flat hearth characterized by the provision of tool means which can be moved into and out of the furnace in the horizontal direction. The tool means is rotatable about its longitudinal axis and has a plate-shaped head on the end introduced into the furnace. The head is substantially per pendicular to the direction of movement and has a straight scraping edge on one side and a tined edge on the opposite side.

DEVICE FOR REMOVAL OF ASII AND SLAG FROM A FURNACE FOR THE BURNING OF WASTEOR THE LIKE The present invention relates to a device for the removal of ash and slag from a furnace having a flat hearth and used for the burning of waste and the like.

Waste substances, and particularly oil containing sludgelike substances, are generally disposed of by burning, since dumping of these substances is not permitted due to the danger to the purity of water in lakes, streams, etc., and ground water. The ash and slag produced upon this combustion must be periodically removed from the furnace. lf galvanic muds are burned, residues (chromates) are produced which must be combined in a water insoluble form, which may be obtained by the addition of certain known substances, for example sulfates, which combine with the liquid slag.

In the methods of combustion for the elimination of waste, for instance oil sludge and galvanic mud, relatively large'quantities of slag may be obtained, and their removal from the furnace must be effected continuously or at regular short intervals of time.

The prior attempts to use rotary kilns for the combustion of waste substances, which produce large quantities of slag upon burning, have not been successful. Rotary kilns, due to the inclination and the continuous rotation, are in most cases satisfactory since they are continuously discharged. However, it has been found in practice that in combustion processes producing large quantities of slag, the slag tends to bake onto the lining of the furnace and can only be removed in a cooled condition.

It has furthermore been found that the burning or burning out of larger objects, for instance barrels or pails which have served for the packing of oil containing substances or oil, paint, etc., is possible in rotary kilns only with great difficulty, if at all.

An object of the present invention is to create an apparatus for the removal of ash and slag from a furnace having a flat hearth and used for the burning of waste which permits an effective removal, during operation, of ash and slag even in cases of the formation of a large amount of slag, and with which barrels, pails or the like can be pushed into the furnace for burning out and removed therefrom.

In order to solve this problem, the invention provides for a furnace for the burning of waste substances or the like, a device for removal of ash and slag which consists of a tool which can be introduced in a horizontal direction into the furnace and removed from it, is rotatable about its longitudinal axis, and has fixed at the end to be introduced into the furnace a head of plate-like configuration, which head is substantially perpendicular to the direction of movement of the tool and has on two opposite approximately parallel sides a scraping edge on one side and tines or the like on the other side, the tool being swingable in planes perpendicular to the plane of the hearth.

The tool is so guided on rollers or skids that it can be removed entirely from the furnace. By rotation around the longitudinal axis, the edge having the tines or the like, which serves to break the layer of slag open, may be directed towards the hearth. The tool is introduced into the furnace with the head somewhat elevated so that the tines will therefore be moved over the layer of slag. Upon the rearward movement the plate-shaped head will be lowered until the tines are introduced into the layer of slag and break it open. This move ment of the tines through the layer of slag can also take place in the direction towards the inside of the furnace. After the layer of slag has been broken open, the tool is pulled entirely out so that the head end also is outside the furnace. Thereupon the tool is turned around its horizontal axis by 180 until the straight edge, which has been referred to as the scraping edge, points downward toward the hearth. Then the tool is again introduced into the furnace in an elevated position so that the scraping edge is moved over the parts of the slag which have been broken up. At the rear end of the furnace the plate-shaped head of the tool is lowered so that the scraping edge contacts the flat hearth and the pieces of slag can be pulled forward. This process is repeated as often as necessary depending on how much material is present.

The tool can be guided in any desired manner. Preferably a carriage is provided in which support means for swinging the tool in the vertical plane are also arranged. This carriage is adapted to be moved horizontally back and forth while carrying the tool. The tool guide preferably also has sharp edged skids which assist in the cutting and breaking open of the layer of slag and whereby the action of the tines on the plate-shaped head is supported.

For the inward and outward movement of the tool, and possibly also for its rotation around the longitudinal axis and its swinging movement in the vertical plane, it is advisable to provide a power drive. This power drive can be programmed if desired.

The shaft which bears the plate-shaped head is preferably a tube provided with water cooling.

The inventive apparatus accomplishes an effective removal of ash and slag, even under difficultconditions, which is anadvantage as compared with operation with rotary kilns, the disadvantages of which for large amounts of slag have been mentioned above. With the inventive apparatus, it is possible to remove slag during operation even if the slag is no longer liquid but has already baked on. Therefore, continuous operation of the furnace is possible which constitutes the prerequisite for a rapid and economical working of oil containing sludge-like waste substances, galvanic muds, or the like.

With the inventive apparatus, barrels or pails can also be inserted directly into the combustion chamber and can be removed therefrom, after their contents have been burned, by the ash or slag removing tool.

The residues which collect on the hearth of a combustion retort during the combustion are broken up at given time intervals by the device during operation and then pulled out after the turning of the tool has taken place. The baking-on of liquid slag is practically impossible, since the slag collects only on the hearth and does not detrimentally affect the furnace walls.

The plate-shaped head can also be of triangular, pentagonal, hexagonal, or any other suitable geometric shape. These embodiments have advantages if, aside from a scraping edge and an edge with tines of given width, length and spacing from each other, also other embodiments of tines are desired such as longer or shorter tines or tines spaced a greater distance from each other.

The means for accomplishing the foregoing objects and other advantages, which will be apparent to those skilled in the art, are set forth in the foregoing specification and claims and are illustrated in the accompanying drawings dealing with a basic embodiment of the present invention. Reference is made now to the drawings, in which:

FIG. 1 is a side elevation of the apparatus in accordance with the invention;

FIG. 2 is a top plan view of the apparatus in accordance with the invention;

FIG. 3 is a section taken along line 3-3 in FIG. 1 on an enlarged scale;

FIG. 4 is a section taken along line 4-4 of FIG. 2 on an enlarged scale; and

FIG. 5 is a section taken along the line 5-5 of FIG. 2 on an enlarged scale.

The combustion furnace 12 has a flat hearth l which may be formed of bricks, tarnped or cast. At the end of the tube 3 which is introduced into the furnace there is fixedly mounted a plate-shaped head 2. The tube 3 is so supported in the guide carriage 4 that it can be swung vertically as well as rotated about its longitudinal axis. This carriage therefore serves as a pivot point for the raising and lowering process (the swinging movement in a vertical plane), The plate-shaped head 2 is so shaped and dimensioned that, upon the rotation of the tube 3 in the carriage 4 when the tube 3 is in horizontal position,

either a straight, smooth knife-like scraping edge 13 rests on the hearth l, or an edge 14 having tines l5 rests on the hearth l. The rotation of the tool takes place outside the furnace and therefore in front of the door of the combustion furnace when the tool has been entirely withdrawn.

The tube 3 is relatively thick in order to be able to withstand mechanical stresses. Within the tube 3 there is arranged a tube 3' (see FIGS. 3 and 5) through which cooling water is fed, the water being circulated to be discharged out of the outer tube 3.

The entire drive unit 5 contains essentially the drive motors for the different movements of the tool, namely the motor 9 for raising and lowering, the motor 10 for the introduction and removal, and the motor 11 for the rotation of the tube 3 and the head 2, each motor being operatively connected to the tube by conventional gear means. The entire drive unit 5 travels on the track 6.

The head 2 preferably consists of heat-resistant cast iron. In the embodiment shown, the edges of the head 2 which extend to the furnace walls are bent at an angle and are sharp-edged so that deposits on the furnace wall can be scraped off and pushed back onto the hearth l.

The apparatus operates as follows:

For the removal ofslag, the head 2 on tube 3 is lifted by the motor 9, the guide carriage 4 serving as a supporting and pivot point. This process takes place outside the furnace. By means of the motor 10, the head 2 and the tube 3 are then introduced into the furnace l2 and lowered as soon as the head 2 has reached the rear of the furnace. If the slag does not have to be torn apart, the operation can start with the straight side or edge 13 of the head 2 (see FIG. 4) directed downwardly. Upon the withdrawal of the tool the residues are pulled out of the furnace. When, however, the slag must first be broken up, the tool is rotated about its longitudinal axis so that the edge 14 of the head 2 which is provided with the tines 15 points downwardly. For breaking apart the slag, the head 2 can be moved back and forth several times, after which the tool is pulled out of the furnace, rotated 180, so that the straight edge 13 of the head 2 points downwardly, and then guided forward while being swung a few degrees in vertical plane around the pivot point in the carriage 4, until the head 2 is again lowered onto the hearth l.

The apparatus can also be employed in the manner that the layer of slag is torn apart and turned over, whereupon the combustion process is for the time being continued in order to effect a more complete and thorough burning of the residues. Thereupon the tool is again introduced into the furnace and the residues pulled out with the straight edge 13 of the head 2.

If oil contaminated earth is to be burned, the head 2 is introduced at fixed time intervals into the furnace or fire zone. The earth to be burned out, which is fed to and introduced into the combustion furnace by some suitable means, for instance, a conveyor belt, is broken up by the head 2 of the tool, turned over and distributed uniformly over the surface of the hearth 1-. In this connection, by swinging in the carriage 4, the desired height of the head 2 above the hearth l is established, so that one obtains the desired thickness of layer for the earth which is to be burned out, this being of importance for complete burning. Upon completion of the burning, the earth is pulled out of the furnace by means of the head 2. This advantageous manner of operation is of particular importance in view of the substantially increased danger of the contaminating of earth by oil running out of tanks or pipelines resulting from the increasing use of mineral oils.

If the furnace installation is to be charged with barrels, pails, or other containers or with other solid waste of larger dimensions, the head 2 may be used as pusher. A delivery table 16 can be arranged in front of the furnace on or in the track 6, the head 2 lowered to the height of the hearth-l or table 16, and then moved in the direction towards the inside of the furnace, whereby the containers or solid waste are forced into the fire zone. After they are completely burned out, the head is lifted to such an extent that it passes above the parts which have been burned out and IS then lowered behind them so as to pull them out.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein.

1 claim:

1. An apparatus for the removal of ash and slag from a furnace having a fiat hearth and used for the burning of waste or the like, said apparatus comprising a tool having a shaft, a plate-shaped head fixedly mounted on one end of said shaft, means to move said tool into and out of the furnace in horizontal direction, means to rotate said tool about its longitudinal axis, said head being substantially perpendicular to the direction of movement and having on one side a straight scraping edge and on the opposite side an edge provided with a plurality of tines, and means to swing said tool vertically.

2. An apparatus according to claim I, further comprising a guide carriage, means on said carriage to support said shaft.

3. An apparatus according to claim 2, in which the means to swing said tool vertically is arranged on said guide carriage.

4. An apparatus according to claim 3, further comprising means on said guide carriage to support said tool for the rotary movement about its longitudinal axis.

5. An apparatus according to claim 2, further comprising sharp-edged skids extending transversely of the carriage to effect scraping of the side walls of said furnace.

6. An apparatus according to claim 1, further comprising first powered drive means for controlling the inward and outward movement of the tool, second powered drive means controlling the rotary movement of said tool about its longitudinal axis, and third powered drive means controlling the swinging movement of said tool in a vertical plane with respect to the plane of the hearth.

7. An apparatus according to claim 1, further comprising drive unit means containing power drive means to control the motions of said tool, and track means for said drive unit means to travel on.

8. An apparatus according to claim 1, further comprising a table adapted to be arranged before an opening to the furnace at the height of the hearth, said table supporting larger objects to be burned during charging and discharging of the furnace.

9. An apparatus according to claim 1, further comprising a continuous feeder for the feeding of material which is to be burned into the furnace. 

